For many years CFCs, of which DuPont's "Freon" is a well known commercial brand, have been the standard heat transfer media in refrigeration units, air conditioners, heat pumps, and the like. The reason for their wide spread use is that CFCs are stable and nonflammable, boil and condense in a useful temperature and pressure range, and were believed relatively inert and free of harmful side affects. Recently, however, a serious impact on the ozone layer of CFCs released into the atmosphere has been discovered, and it is now necessary to avoid open air release of CFCs from equipment which contains them. In the normal use of CFC-containing equipment, the CFC is, of course, constantly recycled and is not released to the atmosphere. However, over time the CFC gradually becomes contaminated in the equipment and loses its effectiveness. The common contaminants include water, air, compressor oil, hydrochloric acid, waxes, varnishes, and the like. Such contamination accelerates the rate of breakdown of the CFC, because it increases compressor operating temperature. Moreover, prolonged operation at higher temperatures can cause compressor or compressor drive failure.
For many years it was common practice in the industry simply to release contaminated CFC to the atmosphere. Now, however, that is no longer acceptable practice; nor is it responsible to abandon CFC containing equipment because it would eventually leak out. It thus is becoming increasingly desirable to service CFC containing units to purify the CFC in them or replace it with pure CFC in a manner which prevents any loss to the atmosphere or the environment.